The present invention is directed to a multi-function control valve assembly for use during open heart surgery to control aspiration of fluid from the left ventricle of the heart.
During open heart surgery, the heart is typically bypassed and the patient's blood circulation is maintained by a heart-lung machine. Moreover, it has been recognized that certain advantages can be gained by decompressing the left ventricle during cardiopulmonary bypass procedures. As such, a drainage tube is inserted into the left ventricle and a pump is used to generate suction for aspirating accumulated blood. To provide means for controlling the rate of aspiration, it is known to install a control valve in the drainage tube between the left ventricle and the pump. In many instances, the control valve functions as a one-way check valve to prevent reverse flow of blood back into the left ventricle in addition to providing both positive and negative pressure relief functions. The positive pressure relief function of the control valve acts to relieve pressure buildups between the pump and the outlet of the control valve. In contrast, the negative pressure relief function of the control valve acts to limit the vacuum pressure in the drainage tube to a desired level. Examples of conventional control valves are disclosed in U.S. Pat. Nos. 4,502,502, 4,642,097, 4,671,786, 4,725,266, 4,758,224, 5,401,255 and 5,707,352. However, despite the existence of such control valves, a need exists to continue development of advanced valving systems which improve upon the art.